1. Field of the Invention
The present invention relates to an electrical connection apparatus for use in the inspection of a semiconductor device and more particularly to an electrical connection apparatus which makes use of a probe sheet.
2. Prior Art
Generally, a semiconductor device such as an integrated circuit (referred to as xe2x80x9cICxe2x80x9d hereinafter) undergoes an electrical test (inspection) for judging whether or not the IC can work faithfully according to a given electrical performance specification. Such electrical test is usually carried out before a semiconductor wafer is separated into a plurality of individual IC chips by cutting, and this test is carried out by means of an electrical connection apparatus such as a probe card provided with a plurality of probes (or probe elements) having a pin point (contactor) each to be pressed on a plurality of corresponding electrodes formed on the IC chip, respectively.
One of the electrical connection apparatus of this kind makes use of a probe sheet including a plurality of probe elements arranged on an insulating film and a wiring board having an opening at its center. Each probe element has a contact portion to be pressed on the corresponding electrode of the IC chip. The probe sheet is fitted to one surface of the wiring board such that the contact portion of the probe element opposes to the opening of the wiring board.
In the prior art electrical connection apparatus like the above, however, the probe sheet is apt to sensitively react to the variation in the ambient temperature and the wafer temperature as well and to thermally expand and contract itself. As a result, the relative positional relation between contact portions themselves and the same between the contact portion and the corresponding electrode of the IC chip become different from the initially designed positional relation, thus some contact portions failing to make a right contact with predetermined corresponding electrode of the IC chip. Especially, in case of the burn-in test in which the wafer is tested in a heat chamber, or in case of the test in which a number of IC chips are tested at the same time, the temperature of the probe sheet rises too quickly to continue the test over a long period of time.
Therefore, it is a main purpose of the invention to provide an electrical connection apparatus for use in the electrical test of a flat plate-shaped object such as an IC chip, in which the relative positional mismatch between the contact portion and the corresponding electrode of the object under test can be obviated or at least minimized.
An electrical connection apparatus according to the invention includes a lattice having a plurality of openings arranged in each of the X- and Y-directions intersecting with each other, and a probe sheet including a plurality of probe elements of which each has a contact portion and is provided in each of the above openings. The probe sheet is arranged on one surface side of the lattice such that the contact portion is positioned so as to correspond to the opening. Furthermore, the probe sheet is divided into a plurality of probe regions which are separated from each other by one or more boundary portions defined between adjacent opening regions each including one or more openings.
When performing the electrical test on a flat plate-shaped object (referred to as xe2x80x9ctest-objectxe2x80x9d hereinafter) like an IC chip formed on the semiconductor wafer, the contact portion of each probe element is pressed on the corresponding electrode of the test-object and then the predetermined voltage and current are supplied thereto. When performing a heating test such as a burn-in test or an electrical test on a plurality of test-objects at the same time, the probe sheet comes to show the thermal expansion because of the temperature rise in the ambience, the semiconductor wafer, and the probe element itself.
In the electrical connection apparatus according to the invention, however, since the probe sheet is divided into a plurality of probe regions which are partitioned from each other by portions corresponding to the boundaries of each opening region, the thermal expansion of each probe element gives no influence to other probe elements adjacent thereto. Also, since the contact portion of the probe element is located so as to correspond to the opening of the lattice, the probe element, especially the relative positional relation of its contact portion, in its turn the relative positional relation of the contact portion against the electrode of the test-object is hardly influenced by the thermal expansion of the probe region. As a result, the relative positional mismatch due to the temperature rise between the contact portion and the electrode of the test-object becomes small.
Each contact portion includes a projection electrode projecting on the opposite side of the lattice. The projection electrode may be in the form of a circular cone or a pyramid. With this, when the projection electrode is pressed on the electrode of the test-object, the sharp top of the projection electrode pierces into the electrode of the test-object or scrapes off the oxide film formed around the electrode of the test-object, and thus the projection electrode can surely make an electrical connection with the electrode of the test-object.
Furthermore, the electrical connection apparatus may include a plurality of elastic members made of rubber or the like, each elastic member being arranged inside the aforementioned opening. The probe sheet may be fitted to the elastic member. With this, when pressing the contact portion on the electrode of the test-object, since the elastic member functions as a reaction body of the probe element, irregularity in the height of the contact portion is absorbed, and thus the contact portion can surely make an electrical connection with the electrode of the test-object.
Still further, the electrical connection apparatus includes a plurality of support members which are arranged on the other surface side of the lattice at a predetermined interval in either X- or Y-direction so as to extend in the other direction, in contact with the elastic members, and also includes a base plate to which the support members are fitted.
The lattice may be made of a material of which the thermal expansion coefficient is smaller than that of a semiconductor wafer. With this, the thermal expansion coefficient of the lattice is made smaller, thus the positional mismatch between the contact portion and the electrode of the test-object hardly taking place.
The support member may project from the lattice on the side opposite to the probe sheet.
The electrical connection apparatus may be further provided with a plurality of wires which make an electrical connection with the probe element and penetrates the lattice to extend further. With this, the electric signal or power for use in the test can be exchanged between the contact portion of the probe element and the electric circuit through this wire.
The electrical connection apparatus further includes one or more film-like connection base plates having a plurality of wirings each of which is connected with the wire as mentioned above. With this, the electric signal or power for use in the test can be exchanged between the contact portion of the probe element and the electric circuit through the wirings of the connection base plate. The wire may extend further, penetrating the base plate as described above.
An electrical connection apparatus further includes a plate-like elastic member arranged in each opening of the lattice and a plurality of support members arranged on the other surface side of the lattice at a predetermined interval in either the X- or Y-direction to extend in the other direction, and in contact with the elastic members. In this electrical connection apparatus, the support member has a groove opened extended in longitudinal direction of the support member and on the elastic member side to receive a part of the elastic members, each probe element extends in the manner of a cantilever with the help of one or more first slits formed in the probe sheet, and the elastic member has a plurality of second slits corresponding to the first slit at least in its portion received in the groove. With this, when the contact portion is pressed on the electrode of the test-object, the probe element formed in the manner of a cantilever is surely curved, thereby enabling the contact portion to surely make electrical contact with and move over the electrode of the test-object keeping the state of being pressed on the electrode of the test-object. Consequently, there is surely caused a rubbing action by the contact portion against the electrode of the test-object.
It is possible to form a space between both of a part of the elastic member and the bottom surface of the groove. With this, the contact portion can surely move with respect to the electrode of the test-object, thereby enabling a rubbing action by the contact portion against the electrode of the test-object.
The projection electrode has a conical or pyramidal shape, and the apex angle thereof has a value in the angular range of 100 through 175 degrees.
If such a projection electrode as described above is pressed on the electrode of the test-object, the apex portion of the projection electrode pierces into the electrode of the latter so that both electrodes are surely and electrically connected with each other. Furthermore, if the projection electrode is pressed on the electrode of the test-object, a certain horizontal component force comes to act on a part of the electrode of the test-object in the direction parallel thereto. However, since the apex angle of the contactor is 100 degrees or more, such horizontal component force is smaller than the component force vertically acting on the electrode of test-object, so that no rise-up or swell of the electrode material takes place.
If the apex angle of the contactor is less than 100 degrees, however, the component force applied in parallel with the test-object from among the force acting on the electrode of the test-object becomes so large that the rise-up or swell of the electrode material comes to take place. On the other hand, if the apex angle of the contactor exceeds 175 degrees, the rise-up or swell of the electrode material does not appear, but the apex portion of the projection electrode fails to pierce into the electrode of the test-object, which results in the incomplete electrical connection between the projection electrode and the electrode of the test-object.
As described above, according to the projection electrode of the invention, despite the fact that the sure electrical connection can be obtained between the projection electrode and the electrode of the test-object, there is prevented the rise-up or swell of the electrode material of the test-object which is caused by the pressure applied relatively between the projection electrode and the electrode of the test-object.
The projection electrode has a regular quadrilateral pyramidal shape, and its apex angle can have a value in the angular range of 100 through 165 degrees. With this, despite the fact that the sure electrical connection can be obtained between the projection electrode and the electrode of the test-object, there is surely prevented the rise-up or swell of the electrode material of the test-object which is caused by the pressure applied between the projection electrode and the electrode of the test-object.
The projection electrode has a polygonal pyramid shape with a plurality of slant planes, one slant line of which is directed to the displacement direction of the projection electrode when viewing it from the apex side of the projection electrode, the displacement being caused by the overdrive of the projection electrode. With this, the sure electrical connection can be attained between the projection electrode and the electrode of the test-object. Furthermore, even if the projection electrode makes a displacement with respect to the electrode of the test-object by the overdrive of the projection electrode, the displacement is made in the longitudinal direction of the above one slant line, so that the component force pushing a part of the test-object electrode in the displacement direction of the project electrode is made smaller. As a result, there is surely prevented the rise-up or swell of the electrode material of the test-object which is caused by the pressure applied between the projection electrode and the electrode of the test-object.
The projection electrode has a regular quadrilateral pyramidal shape, two opposing slant lines of which extend in the longitudinal direction of the probe element including the projection electrode when viewing them from the apex side of the contactor, and make the apex angle with a value in the angular range of 120 through 165 degrees. With this, the projection electrode can more surely make an electrical connection with the electrode of the test-object. Furthermore, even if the projection electrode makes a displacement with respect to the electrode of the test-object by the overdrive of the projection electrode, the displacement is made in the longitudinal direction of the above two slant lines, so that the component force pushing a part of the test-object electrode in the displacement direction of the project electrode is made smaller. As a result, there is surely prevented the rise-up or swell of the electrode material of the test-object which is caused by the pressure applied between the projection electrode and the electrode of the test-object.
The projection electrode has a regular quadrilateral pyramidal shape, two opposing slant planes of which are directed to the longitudinal direction of the probe element including the projection electrode when viewing them from the apex side of the projection electrode, and make the apex angle with a value in the angular range of 100 through 155 degrees. With this, the projection electrode surely can make electrical connection with the electrode of the test-object, and there is surely prevented the rise-up or swell of the electrode material of the test-object which is caused by the pressure applied between the projection electrode and the electrode of the test-object.
The projection electrode has a rhombic pyramidal shape with four slant lines, that is, two each of longer and shorter slant lines. Two opposing longer slant lines extend in the longitudinal direction of the probe element including the projection electrode when viewing them from the apex side of the projection electrode, and make an apex angle with a value in the angular range of 170 through 175 degrees. With this, despite the fact that the sure electrical connection can be obtained between the projection electrode and the electrode of the test-object, there is surely prevented the rise-up or swell of the electrode material of the test-object which is caused by the pressure applied between the projection electrode and the electrode of the test-object because two opposing slant lines extend in the displacement direction of the projection electrode with respect to the electrode of the test-object.
If the projection electrode has a rhombic pyramidal shape, the apex angle made by two opposing shorter slant lines has a value in the angular range of 125 through 135 degrees. With this, since the apex angle made by two opposing shorter slant lines is made acuter than the apex angle made by two opposing longer slant lines, the projection electrode pierces into the electrode of the test-object with ease. Despite of this, there is surely prevented the rise-up or swell of the electrode material of the test-object which is caused by the pressure applied between the projection electrode and the electrode of the test-object.
The projection electrode has an irregular rhombic pyramidal shape, two opposing slant planes of which are larger than the other two opposing slant planes with respect to the length from the bottom surface side of the pyramid to the apex thereof and are directed to the longitudinal direction of the probe element including the projection electrode when viewing them from the apex side of the projection electrode, and make an apex angle with a value in the angular range of 120 through 165 degrees. With this, despite the fact that the sure electrical connection can be obtained between the projection electrode and the electrode of the test-object, there can be surely prevented the rise-up or swell of the electrode material of the test-object which is caused by the pressure applied between the projection electrode and the electrode of the test-object.
The projection electrode can have a circular cone shape and have an apex angle with a value in the angular range of 120 through 165 degrees. With this, despite the fact that the sure electrical connection can be attained between the projection electrode and the electrode of the test-object, there can be surely prevented the rise-up or swell of the electrode material of the test-object which is caused by the pressure applied between the projection electrode and the electrode of the test-object.
The invention will now be described in detail with reference to the accompanying drawings which make up a part of this specification.